In the stunning first season finale, Olivia traveled to an intriguing parallel universe to meet with Massive Dynamic founder William Bell.

Season two opens with her shocking return to this perplexing alternate reality, while Peter, unknowningly in a race aginst time with an ominous mobile force, pursues information about Olivia's visit. Walter reenters the lab to cook up a bit of fringe science, and of course, some custard for Peter's birthday.Fringe case file # 201-91709

original airdate--September 17,2009 rating--7.82 million

network--Fox

songs; Fringe "Main Title Theme" by JJ Abrams

"Can't Find My Way Home" by Green Grass

Glyph code spells--TOWER

Goofs--Lighting equipment is reflected on Nina's sunglasses when she tells Broyles to "save the day" after the Senate hearing.

Just after Olivia wakes up in hospital, she's trying to explain what happened, and we hear a heart monitor getting faster and faster - the doctor looks concerned and says they need to get her pulse down. But when we cut to the monitor itself it shows her heart rate as 72 - a perfectly normal value.

Fringe Event: Shapeshifters

Trivia: When the shapeshifter enters his next "body"'s apartment, The X-Files is briefly visible on the television. The clip shown is one from the episode "Dreamland," which like this episode of Fringe is about characters who switch bodies as a result of cryptotechnology.

There are a number of references to The X-Files. One reference is during the Senate hearing, which itself occurred a number of times during the series run, the committee chairman refers to the defunct "X" division of the FBI.

Goofs: Peter tells Olivia that the Greek phrase she said on waking up was "Na einai kalytero anthropo apo ton patera tou" and translates this as "Be a better man than your father." The Greek is grammatically incorrect (it should be "kalyteros anthropos...") and Peter's translation is wrong. The translation of Olivia's phrase is "May he be a better human being than his father." What Peter said is a translation of the Greek phrase "Na eisai kalyteros anthropos apo ton patera sou."

Just after Olivia wakes up in hospital, she's trying to explain what happened, and we hear a heart monitor getting faster and faster - the doctor looks concerned and says they need to get her pulse down. But when we cut to the monitor itself it shows her heart rate as 72 - a perfectly normal value.